In a dual-fed configuration, two adjacent
converters fulfil the requirement of providing
energised current to the rotor circuit. Grid-connected
converters (GSC), are linked to the grid, and
function with a three-tier power system or three tier
converters, while sustaining a consistent DC
potential. The stabilized DC voltage serves as the
source of power for the three-tier converter
straightly linked to the rotor circuit, commonly
known as a rotor-side converter (RSC).
The primary role of the GSC, is to elevate a
stable DC potential. However, the GSC also
possesses the capability, to regulate imaginary
power, and offset imaginary power during
unbalanced conditions, [3]. Conversely, the
converter RSC supplies the necessary polarization
current, to that rotor winding, facilitating the
generation of crucial dynamic and imaginary power
capabilities at the stator side.
The production of electric power might undergo,
an increase of 2%–6% when utilizing varying hurtle
wind turbines collated to wind turbines with a
persistent rotational speed, [4]. On the contrary, [5],
there is a potential for increasing power by up to
39%. The German brochure and others, [6], depict
that the power produced with varying hurtle wind
turbines can fluctuate in the range of 3% to
28%distinguished with persistent hurtle wind
turbines, hinging on site conditions, and specific
parameters.. Various studies, including others, [5],
[6], [7], [8], [9], have presented the calculations of
the electric power produced by the dfig. A more
thorough examination of comparing the electrical
circuits in wind turbines is needed. In their research,
[10], investigated power generation across various
methods, including a constant hurtle wind turbine
with an asynchronous generator, a wind turbine with
fully varying hurtle capabilities employing an
inverter-supported asynchronous generator, and a
variable-speed wind turbine utilizing a dfig. The use
of a dual supported asynchronous motor, in
performing as generation mode, enhances the
production of electric power. In the context of a
variable-hurtle system, utilizing a wound rotor
asynchronous motor emanates in a 20% increase in
the power of a dfig, and it experiences a 60%
increase compared to a system with a constant
speed.
It's crucial to emphasize that the investigation
did not consider into account losses associated with
wind distribution, electrical components, and
machinery. Introduced and implemented the double-
supported production strategy for reluctance
machines, inspiring initial attempts to utilize cage
rotor asynchronous motors for similar applications,
[11].
The initial deployment of the dfig was
evaluated, [12]. This implementation utilized a
control technique incorporating a Proportional-
Integral (PI) controller to trigger sinusoidal Pulse
Width Modulation (PWM) with a consistent
switching-frequency. Various researchers have
widely adopted this control scheme. A thorough
exploration of the dfig is suggested, incorporating
the determination of rotor position from voltage and
current parameters, [13].
A notable analysis was conducted with A. The
matrix amalgamation, [14], of the DFIG and its
performance in voltage dip. Additionally,
contribution to the field with additional analysis of
the transient model of DFIG done, [15]. Control
strategy of a dfig, employing hysteresis controllers,
to achieve optimal performance, [16].
The converters RSC, and GSC are analysed
autonomously to investigate the dfig. The RSC can
be executed autonomously, prior to a stable DC-
potential, is supplied from the GSC. A grid-side
controller with the capability to manage the DC
potential amidst irregular source voltage situations
were suggested, [17]. However, this configuration
could not address imaginary power compensation.
The operational point of the GSC can be
established based on the operational point of the
RSC, and operational conditions of the generator.
Introduced analysis sustained by non-linear voltages,
[18], and slip regulators for a dfig tied to the grid.
Explored a straight real, and imaginary power
regulators relying on stator hurtle employing a
hysteresis current controller, [19]. An exemplary
vector governing mechanism to modulate the real,
and quadrature powers generated from a dfig, [20],
was devised. Fundamentally, a controller built upon
a dfig is akin to the traditional AVR/PSS, [21]. This
controller assists in upholding the frequency, and
stoutness of the power system voltage.
The paper outlines a hypothetical
implementation of a supervisory system configured
for a wind generator relying on the dfig. The
supervisory scheme employs field-based control for
monitoring the RSC and utilizes a hysteresis
modulator to regulate the GSC. A crucial and critical
function of the dfig is to sustain the stable
operational state of the DC potential.
The RSC approach facilitates, autonomous
control over both real, and quadrature power in a
dfig through the regulation of rotor-currents. The
effectiveness of these control methods, is closely
tied to the machine electrical attributes, and the
transitions occurring within its reference structure.
WSEAS TRANSACTIONS on POWER SYSTEMS
DOI: 10.37394/232016.2023.18.42
Ankineedu Prasad Padamata,
Dr. Gudapati Sambasiva Rao